A simple JavaScript function that doubles every character on a web page – useful when testing layouts for i18n issues

pseudolocalize.js

// Paste this function to your browser’s JavaScript console,
// and then run it, passing in a CSS selector, eg:
// > pseudolocalize('body')

var pseudolocalize = function pseudolocalize(arg){
    if(typeof arg === 'string'){
        var elements = document.querySelectorAll(arg);
        for(var i=0, len=elements.length; i<len; i++){
            pseudolocalize(elements[i]);
        }
    } else if(arg.nodeType === 1){
        for(var i=0, len=arg.childNodes.length; i<len; i++){
            pseudolocalize(arg.childNodes[i]);
        }
    } else if(arg.nodeType === 3){
        arg.nodeValue = arg.nodeValue.replace(/(.)/g, '$1$1');
    }
}

pseudolocalize.min.js

var pseudolocalize=function e(l){if("string"==typeof l)for(var o=document.querySelectorAll(l),d=0,n=o.length;n>d;d++)e(o[d]);else if(1===l.nodeType)for(var d=0,n=l.childNodes.length;n>d;d++)e(l.childNodes[d]);else 3===l.nodeType&&(l.nodeValue=l.nodeValue.replace(/(.)/g,"$1$1"))};